A semiconductor substrate has a first surface and a second surface that includes an inner region and an outer region. The semiconductor substrate includes a drift layer of a first conductivity type and a terminal well region of a second conductivity type. The terminal well region includes a portion that extends from between the inner region and the outer region toward the outer region. A first electrode is on the first surface. A second electrode is on at least part of the inner region and electrically connected to the terminal well region, and has its edge located on a boundary between the inner region and the outer region. A peripheral structure is provided on part of the outer region, away from the second electrode. A surface protective film covers the edge of the second electrode and at least part of the outer region and has the peripheral structure engaged therein.

A silicon carbide epitaxial substrate according to a present disclosure includes a silicon carbide substrate and a silicon carbide epitaxial layer disposed on the silicon carbide substrate. The silicon carbide epitaxial layer includes a boundary surface in contact with the silicon carbide substrate and a main surface opposite to the boundary surface. The main surface has an outer circumferential edge, an outer circumferential region extending within 5 mm from the outer circumferential edge, and a central region surrounded by the outer circumferential region. When an area density of double Shockley stacking faults in the outer circumferential region is defined as a first area density, and an area density of double Shockley stacking faults in the central region is defined as a second area density, the first area density is five or more times as large as the second area density, the second area density is 0.2 cm.sup.−2 or more.

The present disclosure relates to: a MOSFET device which is applicable to a semiconductor device and, particularly, is manufactured using silicon carbide; and a manufacturing method therefor. The present disclosure provides a metal-oxide-semiconductor field effect transistor device which may comprise: a drain electrode; a substrate disposed on the drain electrode; an N-type drift layer disposed on the substrate; a plurality of P-type well layer regions disposed on the drift layer and spaced apart from each other to define a channel; an N+ region disposed on the well layer regions and adjacent to the channel; a P+ region disposed at the other side of the channel; a gate oxide layer disposed on the drift layer; a gate layer disposed on the gate oxide layer; and a source electrode disposed on the gate layer.

A power SiC MOSFET with a built-in Schottky rectifier provides advantages of including a Schottky rectifier, such as avoiding bipolar degradation, while reducing a parasitic capacitive charge and related power losses, as well as system cost. A lateral built-in channel layer may enable lateral spacing of the MOSFET gate oxide from a high electric field at the Schottky contact, while also providing current limiting during short-circuit events.

A vertical field effect transistor. The vertical field effect transistor includes: a drift area; a semiconductor fin on or above the drift area; a connection area on or above the semiconductor fin; and a gate electrode, which is formed adjacent to at least one side wall of the semiconductor fin, the semiconductor fin, in a first section, which is situated laterally adjacent to the gate electrode, having a lesser lateral extension than in a second section, which contacts the drift area, and/or than in a third section, which contacts the connection area.

A driving apparatus for driving a switching device is provided, the driving apparatus including: a high potential line; a high-potential-side switching control unit configured to perform switching as to whether to connect a control terminal of the switching device to the high potential line; a first resistor element located on a high-potential side and disposed in series with the high-potential-side switching control unit on a path from the control terminal of the switching device to the high potential line; a high-potential-side capacitor provided in parallel with the first resistor element on the path from the control terminal of the switching device to the high potential line; and a high-potential-side discharge control unit configured to control whether to discharge the high-potential-side capacitor.

After trench etching but before formation of a gate insulating film, a 15-minute to 60-minute heat treatment under a mixed gas atmosphere containing nitric oxide gas and nitrogen gas at a temperature from 1200 degrees C. to 1350 degrees C. and a 30-minute to 75-minute heat treatment under a nitrogen gas atmosphere held at the temperature of the 15-minute to 60-minute heat treatment are successively performed, oxidizing etching damage of inner walls of trenches. The total treatment time of the heat treatments includes a total time of at least 90 minutes when the temperature is a predetermined maximum temperature. The oxide layer of the trench inner walls is removed, exposing a clean face. Emission intensity of band edge emission for SiC obtained by CL analysis of surface areas of the inner walls of the trenches is at least equal to the emission intensity of the band edge emission for SiC obtained by the CL analysis of a surface free of dry etching.

A silicon carbide MOSFET device that includes a silicon carbide substrate of a first dopant type; a first silicon carbide layer of the first dopant type on top of the silicon carbide substrate; a second silicon carbide layer of a second dopant type embedded in a top portion of the first silicon carbide layer; a third silicon carbide layer of the first dopant type embedded in a top portion of the second silicon carbide layer; a gate oxide layer overlapped to the first silicon carbide layer, the second silicon carbide layer and the third silicon carbide layer; and a fourth silicon carbide layer at least partially overlapping with the second silicon carbide layer along a direction normal to the silicon carbide substrate. The first silicon carbide layer has lower doping than the silicon carbide substrate and defines a drift region. The third silicon carbide layer has higher doping than the first silicon carbide layer. The third silicon carbide layer includes a plurality of third portions that run substantially along a first direction. The second silicon carbide layer includes a plurality of second portions that run substantially along the first direction. The fourth silicon carbide layer includes a plurality of fourth portions that run substantially along a second direction perpendicular to the first direction. The first and second directions each is parallel to the silicon carbide substrate. The transversely arranged P+ regions to N+ regions in some embodiments allow adequate P+ area to achieve good body diode performance and protection to the gate oxide, but without consuming significant area of the MOSFET cell.

An improved SiC trench MOSFET having first and second type gate trenches for formation of a gate electrode, and a grounded P-shield region under the gate electrode for gate oxide electric-field reduction is disclosed. The gate electrodes are disposed into the first type gate trench having a thick oxide layer on trench bottom. The grounded P-shield region surrounding the second type gate trench filled up with the thick oxide layer is connected with a source metal through a grounded P region. The device further comprises a current spreading region surrounding the first type gate trench for on-resistance reduction.

A type, size, and location of a crystal defect of an epitaxial layer of a semiconductor wafer containing silicon carbide are detected from a PL image by crystal defect inspection equipment. Detected crystal defects include a triangular polymorph stacking fault generated in the epitaxial layer during epitaxial growth and high-density BPDs extending from the stacking fault and present bundled between the stacking fault and a perfect crystal. Next, a chip region free of the triangular polymorph stacking fault and free of the high-density BPD in a specified area that is in the termination region and is located closer to a chip center than is a specified position is identified as a conforming product. A semiconductor chip set as a conforming product may contain high-density BPDs outside the specified area.